Multi-SIM (subscriber identification module) wireless devices have become increasing popular because of their flexibility in service options and other features. One type of multi-SIM wireless device, a dual-SIM dual standby (DSDS) device, enables both SIMs to be in idle mode waiting to begin communications, and but one at a time to participate in an active communication due to sharing of a single RF transceiver. Other multi-SIM devices may extend this capability to more than two SIMs, and may be configured with any number of SIMs greater than two.
Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the UMTS Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). The UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (W-CDMA), Time Division—Code Division Multiple Access (TD-CDMA), and Time Division—Synchronous Code Division Multiple Access (TD-SCDMA). The UMTS also supports enhanced 3G data communications protocols, such as High Speed Packet Access (HSPA), which provides higher data transfer speeds and capacity to associated UMTS networks.
In some wireless networks, a user equipment (UE) can have multiple subscriptions to one or more networks (e.g., by employing multiple subscriber identity module (SIM) cards or otherwise). Such a UE may include, but is not limited to, a dual-SIM, dual standby (DSDS) device. For example, a first subscription may be a first technology standard, such as Wideband Code Division Multiple Access (WCDMA), while a second subscription may support a second technology standard, such as Global System for Mobile Communications (GSM) Enhanced Data rates for GSM Evolution (EDGE) (also referred to as GERAN). Where the UE utilizes a single transceiver to communicate over the multiple subscriptions and/or networks, the UE can tune the transceiver to a given subscription and/or network during a given period of time to communicate therewith, but can only communicate in a single subscription and/or network at a given period of time. As such, when the UE has an active call with the first subscription, the UE may periodically tune away to the second subscription to monitor signals or acquire a connection. During such tune aways, the UE loses downlink information on the active call with the first subscription due to the inability to receive signals corresponding to the first subscription. Further, if the tune away mode persists for a relatively long time, then the network managing the active call of the first subscription may determine that the UE is no longer connected due to lack of activity, and thus may terminate the active call of the first subscription.
Furthermore, a DSDS UE may initially establish an active session on the first subscription, wherein the active session may use a shared radio resource for the majority of the time when the second subscription is in an idle state. Because the device has the second subscription, however, the device may also be required to periodically allow a second subscription to utilize the shared radio resource on the device. Such operation may be referred to as a “tune away” in the DSDS device.
In some situations, such as where the UE reselects a new cell for first subscription service, the UE may receive a master information block (MIB) that contains scheduling information regarding the timing of individual system information blocks (SIBs). The first subscription is often required to receive and decode the SIBs to receive important control information. In legacy systems, these SIB periods sometimes overlap with tune away periods, which may be referred to as “collision” of the two types of periods. Naturally, only one of these two operations may be completed at a given time where there exists a single radio resource, and legacy devices and networks typically prioritize receiving the SIB blocks associated with the first subscription over tune away to the second subscription to ensure that the ongoing data session on the first subscription is maintained. By prioritizing the SIB receive operations to tuning away, the second subscription may not receive pages destined for the second subscription from the second subscription network. As a result, the second subscription may miss one or more calls due to the SIB receive operations trumping tune away. Therefore, improvements in the operation of tune always are desired.